With her career cresting after a best actress Oscar win in 2010 for The Blind Side, SandraBullock made an unlikely move. She quietly put acting on hold, sweeping aside the torrent of offers. "I really had no desire to work at that time," recalls Bullock, who was a new mother in the middle of a very public divorce from motorcycle personality Jesse James.

But director AlfonsoCuaron flew to Bullock's home in Austin to discuss his space odyssey Gravity and coax her back from exile. "We didn't talk about space or technology," explains Cuaron. "We only talked about feelings. The theme of adversity was something very fresh in her life. We spent a whole evening just discussing how it shapes your life."

Three years later, Bullock is being hailed for Gravity and a performance that perhaps is a career best -- a role so challenging that it required the actress to complete most of her scenes isolated in a light tube without sound. The fact that the film, opening Oct. 4, also holds great box-office potential reflects Bullock's own career arc and its melding of high quality and commerciality.

"By the end [of our meeting], I still wasn't sure how I would execute a project like this," says Bullock. "But I met someone whom I had a great connection with. It made it a lot easier to answer, 'Am I going to pass up this once-in-a-lifetime opportunity?' "

Guided by longtime CAA agent KevinHuvane, Bullock, 49, has built one of Hollywood's most enduring careers by seizing opportunity at the precise moment and avoiding the overexposure that has toppled many others. She first cracked the highest echelon of film stars nearly two decades ago with her breakout action hit Speed. Since then, she earned a perch as one of the most bankable actresses with such hits as While You Were Sleeping, Miss Congeniality, Crash and The Proposal, oscillating between romantic comedies and heavy dramas.

Since winning the Oscar, Bullock only has shot three films: the post-9/11 drama Extremely Loud & Incredibly Close, Gravity and summer hit The Heat, which has earned $218 million worldwide. The three films showcase a range that few could have anticipated back when Hollywood had branded her the girl next door. In the case of Gravity, she carries the film almost entirely on her padded spacesuit (co-star GeorgeClooney enjoys far less screen time). "She brings a real strength, a real physicality," says Gravity producer DavidHeyman. "But she also brings a tenderness and vulnerability. It's a rare combination."